英语翻译Why are manhole covers round rather than square?The answ
英语翻译 Why are manhole covers round rather than square? The answer interviewers consider the best is that a square cover could fall into its hole,injuring someone or getting lost underwater.This is because the diagonal of a square is 根号2 (1.414...) times its side.Should you hold a square manhole cover near-vertically and turn it a little,it falls easily into its hole.In contrast,a circle has the same diameter in all directions.The slight recess in the lower part of the cover prevents it from ever falling in,no matter how it's held.